Reproducing apparatus for light sensitive reproduction media



JUL 12, 1943. F. w. voN MEISTER ErAL 2,308,130

REPRODUCING APPARATUS FOR LIGHT SENSITIVE REPRODUCTION MEDIA /2/ ,a l lINVENTORS TH EIR ATTORNEYS Jah. 12, 1943. F. w. voN MEISTER HAL2,308,130

REPRODUCING APPARTUS FOR LIGHT SENSITIVE REPRODUCTION MEDIA Filed Feb.l, '1939 8 Sheets-Sheet 2 Frederiks/r M 2.21971. Mea-te OM n t am 5 Mvv.5 Am a m w.. n m m T i n .e m m m w W T Jn- 12, 1943. F. w. VON MEISTERET AL 2,308,130

REPRODUCING APPARATUS FOR LIGHT SENSITIVE REPRODUCTION MEDIA Filed Feb.l, 1939 8 Sheets-Sheet 3 @las Fredemc/r I4( von Malte/er Fredem'c/r W.Andrey INVENTORS THEIR ATTORNEYS Filed Feb. l, 1959 8 Sheets-Sheet 4 ,EW6 49 ai@ l l l I l l l l l l l uml- F/'edewLc/r l/l( von MasterFede'rL'c/f' V14 Andrew INVENTORS TH El R ATTORNEYS Jan- 12, 1943. F. w.voN MEISTER ETAL 2,308,130

REPRODUCING APPARATUS FOR LIGHT SENSITIVE REPRODUCTION MEDIA Filed Feb.l, 1939 8 Shee'tS-Sheet 5 lll /43 ou Frederick M von Mezlater FrederzlckIV. Andrew `INVENTOR5 THEIR ATTORNEYS Jan. 12, 1943. F. w. voN MEISTERETAL 2,308,139

REPRODUCING APPARATUS FOR LIGHT SENSITIVE REPRODUCTION MEDIA Filed Feb.l, 1939 8 Sheets-Sheet 6 Fredemck I4( Vani/Mendez Frederick W. AndrewINVENTORS BY @M55 Q THE! R ATTORNEYS Jam 12, 1943- F. w. voN MEISTERETAL 2,308,130

REPRODUCING APPARATUS FOR LIGHT SENSITIVE REPRODUCTION MEDIA File Feb.1, 1939 8 sheets-sheet 7 Wyo 114 a EW j@ ump' IIIIIIII IIIIIHHIIIINVENTORS TH EIR ATTORNEYS Jan. 12, 1943. F. w, voN MEISTER ETAL2,308,130

REPRODUCING APPARATUS FOR LIGHT SENSITIVE REPRODUCTION MEDIA Filed Feb.l, 1939 8 Sheets-Sheet 8 Wzg 2@ Fredom'ck IM 'von MeIlser /J' FrederalckI4/. And/few INV ENTO R5 BYML QL* TH EIR ATTORNEYS Patented Jan. 12,1943 REPRODUCING APPARATUS FOR LIGHT SENSITIVE REPRODUCTION MEDIAFrederick W. von Meister, New York, and Frederick W. Andrew, Glen Head,N. Y., assignors, by mesn'e assignments, to General Aniline & FilmCorporation, New York, N. Y., a corporation of Delaware ApplicationFebruary 1, 1939, Serial No. 253,956

8 Claims.

The invention relates to reproducing iparatus for light-sensitivereproduction media, particularly that type of reproduction media whichreproduces positive copies from positive originals and which isdeveloped in a dry state by exposure to a gaseous developing medium.

Reproduction media of this kind are known as diazotype layers. They areproduced by treating the surface of a suitable base, generally paper,with a solution of two dye components, one of which is a light-sensitivebody called the diazo component and the other, which is called acoupling component, is a compound capable of reacting, under suitableconditions, with the diazo component to form a dye. The diazo componentof such a light-sensitive layer is most sensitive to light emissionbetween the 3600 to 4200 line. Such rays effectively decompose the diazocomponent, so that it can no longer combine with the coupling componentto form a dye. Thus. when a diazotype layer is exposed, under anoriginal tracing, design, printed sheet or other work piece to becopied, to a source of light furnishing rays in the '3600 to 4200 line,the diazo component, in those areas which are not protected by the solidlines of the tracing, or design, or letters of the printed sheet, isdecomposed. Upon subsequent development, a dye forms only in the areaswhich were protected from the iight by the solid lines of the tracing,

or design, or letters of the printed sheet. Those areas which wereunprotected and, hence, exposed to light, will be colorless, and thusthe design of the original will be reproducedin color, on a colorlessbackground. Since development of these diazotype light-sensitive layersis effected by contacting the exposed reproduction with a gaseousdeveloping medium, such as ammonia gas, out of contact with anymoisture, no shrinking occurs and an exact dimensional replica isobtained from which true readings can be taken.

It has been suggested. in connection with some types of photoprintingapparatus, particularly the type using .so-called blue print paper asthe light-sensitive medium. to thread a continuous web nf thelicht-sensitive medium through the train of apparatus including theprinter, Washers and driers (which latter, in the case of blue printpaper, constitute the developer). The disadvantage of such continuousblue print machines and developers lies in the waste of blue print paperat the trimming end of the machine, where the continuous web of finishedprints is trimmed by hand to the size of the drawing which has beenprinted thereon. Such trimming by hand is not very neat and consumesmuch time and causes waste. Where quantity production at high printingspeeds is involved and when the drawings to be printed are not of thefull width of the sensitized paper web, it is impossible to cover theentire surface of the sensitized material when using a continuous web.Obviously, substantial quantities of the sensitized paper areWastedbetween 20% and 30% is frequently experienced. It has recentlybecome the tendency of the engineering profession to Standardize thesize of drawings, thereby making it practical to use sensitizedmaterials in sheet form cut to the dimensions of the standard sizeddrawings. With wet or moist developing processes, as in the case of blueprint paper, the'handling of such cut sheets through the developingbaths or machines involves diiliculties. In the case of the diazotypedry developing process, the handling of cut sheets from the exposingmachine or printer to the developing machine is more feasible andpractical at ordinary printing speeds: However, when large production atrelatively high printing speeds is required, the separation of theoriginal drawing from the exposed cut sheet of diazotype paper and thedelivery of the latter to the developer presents a diiiicult problem inhandling for the operator feeding the printing machine. It is,therefore, an object of this invention to provide a means forautomatically separating the original from the reproduction or diazotypecopy.

Many and various sources of light have been suggested and used in thepast for the exposure of light-sensitive reproduction media. At rst,when blue print paper began to be widely used for making photoprintcopies of drawings and other records, the necessary exposure to lightwas accomplished in sun or daylight by the use of sunframes. With theever increasing volume of such work, due to industrial development, thistype of exposure was soon discarded as `too slow and unreliable.Artificial sources of light were sought. Incandescent lamps were used,but in order to raise the light emission of such lamps in the 3600A.-4200 line, to which both blue print solutions and diazo compounds aremainly sensitive, it is necessary to operate them at higher voltagesthan bulb life considerations permit. Furthermore, the light emitted bythe incandescent lamps is particularly rich in wave lengths over the4000 A. line, which are of no use for the purpose whatever. It,therefore, is a wasteful source to use both from the standpoint ofcurrent consumption and replacement. The carbon arc lamp, especially ofthe enclosed type, and the low pressure mercury vapor tube were found toemit a satisfactory amount of those rays to which blue print paper anddiazotype papers are sensitive. Both of these light sources have beenused for many years for the exposure of these sensitized materials. Bothhave definite disadvantages. The carbon arc emits light from arelatively small point and, therefore, must be placed at an appropriatedistance from the sensitized material to attain equal light distributionover the entire surface which is to be exposed. Where a number of carbonarcs are installed, the problem of even light distribution is even morecornplex. In exposure units employing revolving light transmittingcylinders having arc lamps located inside the revolving cylinder, thearc lamp must be of small structural size and have short carin theaccompanying drawings,

1 broken away, to more clearly illustrate the printer bons and thecylinders must be of relatively large diameter to accommodate not onlythe are lamps but also the automatic electro-mechanical cary bonadjusting mechanisms. Since light intensity,

at the point of use, varies inversely as the square of the distance, itis obviously a disadvantage to have to surround the source of light witha cylinder of large diameter. With these disadvantages of prior exposuremachines in mind, it is a further object of our invention to provide asource of light within a glass cylinder of small diameter, which sourceof light will distribute rays of equal intensity over the entire surfaceof said cylinder.

Various devices for carrying excess heat developed by the light sourceaway from the glass cylinder or envelope containing the light sourcehave been suggested. These known devices consist, for the most part, ofordinary propeller blade fans positioned at one end of the lightchamber. Deection fins are sometimes used to insure proper circulationof the cooling air coming from the fan. Due to the intensity of the heatdeveloped when enclosures of small diameter are used, these methods ofcooling have proven inadequate. When a sufficient volume of air is blownthrough the light chamber to maintain acceptable temperatures on theprinting surface, that is, temperatures that would not adversely aiectthe chemicals used, for instance, in drydeveloping dazotype papers, thenthe light source becomes overcooled, resulting in a marked decrease inthe intensity of the light emission. It is, therefore, still a furtherobject of our invention to provide a means of cooling the printingsurface of vthe light chamber suficiently to maintain satisfactoryprinting temperatures without cooling the light source below itsefficient operating temperature.

It has been found that printing media of the diazotype are susceptibleto temperature differentials. Thus, if one end of the printing surfacebecomes appreciably cooler than the other, the printing speed at thecool end will be slower than it is at the warm end. This conditionobtains in spite of the fact that the light intensity may be uniformover the entire printing surface, since the decomposition of the diazocompound by the light is favored by heat. Unless, therefore,approximately even temperatures can be obtained over the whole printingsurface, uneven exposure will be the result. It is, therefore, anotherobject of this invention to provide cooling means which will cool theentire surface to approximately the same temperature.

These and other objects are accomplished by the machine hereinafter morefully described and mechanism.

Figure 2 is a front view of the lower portion of the printer.

Figure 3 is a detail sectional view of electrical connections for thelamp showing blower ducts.

Figure 4 is a detail view of the left upper portion oi Fig. 3, showingthe movable shade adjustment mechanism in section.

Figure 5 is a side view taken on line 5-5 of Fig. 3, showing shadeassembly and adjustment mechanism and rack.

Figure 6 is a detail view of the electrical terminals within the lamphousing.

Figure 7 is an end sectional view of an alternate printer assembly,showing a cylindrical envelope for the light source.

Figure 7a is the same view as Fig. 7, but showing a curved envelope forthe light source.

Figure 8 is a part sectional view, showing the relation of the pick-offi-lngers with the print cylinder.

Figure 9 is a top view of Fig. 7, with the section enclosed in line @-9removed.

Figure 10 is a sectional view through line Ill-IB of Fig. 3, showingwheel attachment to lamp assembly for removal thereof.

Figure 11 is a top view of the tracks or guides at the left end of theglass cylinder.

Figure l2 is a top view of the tracks or guides at the right end of theglass cylinder.

Second modification Figure 13 is a sectional end view of the interior ofthe machine.

Figure 14 is an end view of the drive mechanism for this modification.

Figure 15 a fragmentary front sectional view of the suction roller usedin this modification at the drive end.

Figure 16 is a fragmentary top sectional view of Fig. 15.

Figure 17 is a side view of Fig. 15 on line l1-|1.

Figure 18 is a front elevation of this modification with parts shown insection.

Figure 19 is a detail drawing of the blower ducts and lamp connection atone end of the printing cylinder.

Figure 20 is an enlarged detail drawing of the mechanism for adjustingthe position of the movable light shield.

These illustrations constitute two complete modications of theinvention. Figures 1 to 6 and 8 to 12 constitute one complete assemblywhich is conveniently designated as modification I, while Figures 13 to20 constitute another which is designated as modification II. Figures 7and 7a represent alternate printer assemblies that can be substituted ineither modification I or II. Modification I is our preferredmodification, to which particular Vreference is had in the followingdescription. The structural distinctions between the two modificationswill be pointed out at the end of the detailed description of thepreferred modification. Common elements are designated by likecharacters in the various views.

Referring now to the machines illustrated in these drawings, thecharacter C designates a casing of any suitable structural materialwhich encloses the machine as a whole. The character A designatesgenerally the printing portion of the mechanism, and the character B thedeveloping portion thereof. The actual printing or exposure area ofportion A consists of an outer revolvable glass cylinder of relativelysmall diameter, an inner stationary glass cylinder 2| of still smallerdiameter, and a single high pressure mercury vapor arc tube 22 withself-starting activated electrodes. These' two concentric glasscylinders and the mercury vapor tube which they encompass may be of anydesired length, depending upon what type ofv work is to be handled bythe machine. However, it is desirable and advantageous to have themercury vapor tube and glass cylinders not less than long, in order toequip the machine for the handling of wide rolls of printing media aswell as small cut sheets. In the illustrated modifications of ourinvention, the exposure or printing assembly is designed to accommodatea 46" lamp. In the space between the inner and outer glass cylinders arepositioned two light shields. One of these is a stationary fixed shield23 which covers the throat of the vprinting cylinder, thus protectingthe light-sensitive materials from premature exposure and the operatorfrom the intense glare of the light,

Well as by speed control, to control the total amount of light reachingthe printing surface for exposure. As is illustrated in Fig. 3 and indetail in Figs. 4 and 5, the stationary shield 23 is rigidly affixed tothe inner lamp housing 25 at each end of the glass cylinder 20 by meansof a pair of angle members 26. These angle members also serve to supportthe guide 21 for the sliding or adjustable shield 24. To the outersurface of the sliding shield at each end is attached a block member 28which carries rigidly aixed thereto a plate member 29. Each plate memberhas affixed to its outer extremity a curved rack 30, which engages apinion 3i attached by means of collar 32 and set screw 32a to a bar 33,which latter extends through the outer lamp housing 34 and carries onits outer extremity still another pinion 35. This outer pinion engagesrack 35, which is attached through rod 31, to a manually operated knob38. A stop collar 39 is provided on rod 31, to prevent pulling the rack38 off the pinion 35. Removable link 39a allows for convenientlyremoving the rack within the lamp assembly.

Lamp assembly and electrical connections The burner or lamp assembly forthis machine consists of a 46" quartz envelope high pressure mercuryvapor arc tube 22 having self-starting activated electrodes, which hasits electrode extremities embedded in receptacles 40. Surrounding theelectrodes are metal envelopes or tubes 4|. which are separated from theelectrical connections by insulators 42. These metal envelopes serve toprevent excess cooling of the electrodes. At either end of the lampassembly (Figs. 3 and 6), the electrodes are connected With the currentsource by means of a slip receptacle 44 which consists of a prong ormale member 45 which ts tightly into a tong or female member 43. Theprongs 45 are connected to the respective electrodes, while the tongs 43are connected to the current source. The wires leading to the tongs 45are carried to the outside of the machine through insulator 46, thelatter being journaled in the outside housing plates 48 and 55,respectively, by means of packing ring 49. At one end of the lamp (leftside of Fig. 3), the wire 41 connected to tong 43 is carried through apipe 5l, bent in the shape of a handle to a slip connection 50 in a.terminal box 5|, mountedlon the air duct 52. An electrical housing 54containing insulator 56 is attached to the terminal end of the bent pipe5I, thus insuring safe and rigid contact of the slip connection 50.

In order to facilitate removal of the burner or lamp assembly, Wheels 51,are provided at either end of the lamp, suspended on carriages 58,which are mounted onthe bottoms of the inner housing 25. At the left end(Fig. 3) of the burner assembly, the wheel carriage 58 is held rigid bya bar member 59 affixed to the removable plate 55. To remove the entireburner assembly, then. it is only necessary to remove the two screws 60,which hold the removable plate 55, to the outer housing 34 and pull thebent pipe handle 53 to the left. This will break the electricalconnection at the right end slip contact 44 and left end slip contact50, and even if the operator had neglected to open the switch of themain supply line, there would be no danger of injury by shock. Thewheels 51 will engage guide tracks 52 and 63 provided at either end ofthe outer glass cylinder. When the wheels at the right side of theassembly reach the edge of the outer housing 34 at point X, they leavethe guide tracks 63 and travel along the inner surface of the outerglass cylinder until they reach the left end thereof, at which point, Y,they engage the guide tracks 62 provided on that side of the assembly.As shown in detail in Fig. 10, it is preferable to have two sets ofwheels 51 at each end of the assembly and, as shown in Fig. 12, it ispreferable to provide a wide opening to the guide tracks 63 at the rightend of the assembly, to insure easy engagement of the wheels 51 with thetracks 63 upon leaving the glass cylinder when returning the assembly toposition.

Cooling of the burner The system designed for cooling the outerrevolving glass cylinder and the inner stationary glass cylinderprovides for alternately injecting air through the burner assembly, rstfrom one end and then from the other. This provision allows formaintaining a uniform temperature over the surface of the revolvingglass cylinder. It also equalizes the temperature of the tube so as tolessen the chances of uneven light emission or thermal stresses on thetube seals and walls. Provision is also made for metering only enoughair into the stationary inner glass cylinder and, hence, around themercury vapor arc lamp, to cool the lamp down to its criticaltemperature. By critical temperature, we mean that temperature in thetemperature-light intensity curve of the lamp below which the lightintensity drops off rapidly and, hence, below which only minor decreasesin temperature, by cooling, will cause substantial losses in intensity.This rapid loss in intensity by cooling is caused by a drop in themercury vapor pressure, due to the lowering of the temperature of theenvelope of the lamp. This system of cooling the lamp and printingsurface, which consists of the following cooperating elementsillustrated in our preferred embodiment, allows for placing the print tobe exposed mueh closer to the source of light than has heretofore beenpossible: A blower 64, having air vintake 65 and air lter 66, is drivenfrom motor 51. This blower forces air into the main air duct 68 andthence into one or the other of the branch ducts 69 and 10. Analternating or flip valve 1I directs the flow of air. In the positionshown in Fig. 2, the air will be directed to the left branch-duct 69.This flip valve 1I is caused to change its position so as to first cutoff one branch duct and then the other by a Geneva movement 12, which isactuated from the blower drive shaft 13 through reduction gears 14 andshaft 15. Thus, as the disc 16 carrying arm 11 is revolved slowly in aclockwise direction, the pin 18 will disengage slot 19 and will nextengage slot B as the disc 16 continues to revolve clockwise. In thedownward stroke, being thus engaged with the slot 80, the arm 11 and piny18 will pull the flip valve through an angle of 90 which obviouslyshuts o the left hand branch duct 69 from the blower, and opens up theright hand branch duct 1B. The next revolution of the disc again opensup the left duct 69 and closes the right duct 10, and so on. The blower64 operating through this alternating valve arrangement is sodimensioned that a reasonably high static pressure is generated in theair ducts. The greater portion of the air coming from the one branchduct 52 or the other, B I as seen in Fig. 3, enters the space betweenthe outside of the stationary inner glass cylinder 2l and the inside ofthe outer revolving glass cylinder 28. A small portion of the air ismetered into the space between the mercury vapor tube 22 and the insideof the inner glass tube 2l through the metering holes 1la, provided inthe inner housing 25. The heated air in any given cycle of thecirculation passes out of the burner assembly into the branch ductopposite to the one through which the cool air has entered. Thence, itis carried out through outlet 8|.

When mercury vapor arc tubes of lesser intensity are used in place ofthe high intensity tubes particularly described herein, it is possibleto either seal the tube within the inner glass cylinder and ll the spacearound the tube with an inert gas or to merely mount the tube within theinner glass cylinder after the manner shown in the drawings, butomitting the metering holes 11a. In either case, the tube will becompletely enclosed in a jacket and there will, therefore, be nocirculation of the cooling media in the space between the tube and theinner glass cylinder. Since the air or other inert gas occupying thecompletely enclosed space surrounding the mercury vapor arc tube isstatic or does not become changed during the operation of the machine,cooling is effected by radiation of the heat to the inner glass cylinderand removal of this heat by blowing air across the outer surface of theinner glass cylinder. The circulation of air across the outer surface ofthe inner cylinder, that is, through the ring-shaped space between theinner cylinder and the outer revolving cylinder may be effected by4alternately reversing the current of air as described above or if thepath of travel from one end of the outer cylinder to the other issufciently short to insure that the temperature gradient between theleft and right ends of the cylinder is not great enough to make anyappreciable difference in printing speed, then the cooling air may beblown through continuously in one direction.

We have found that in using the long high pressure mercury vapor lampwhich combines the advantages of high intensity, even light emissionover the entire width of the sensitized material, and close proximity 0fthe light source to the material to be exposed', it is essential thatthe inner stationary glass cylinder arrangement be lines.

used in connection with the mercury vapor lamp, since the mercury Vaporarc is a source of powerful radiation over a Wide band of the spectrum.Only a small portion of this band is required and needed for theprinting of diazotype and similar light-sensitive materials. This band,as explained above, is between the 3600 A. and 4200 The balance of theradiation of the light source is not required for printing, and sincethe quartz envelope of the lamp transmits a very wide range of thisradiation and also those rays which cause sunburn, a glass is used forthe inner as well as the outer revolving cylinder vwhich will absorb theharmful rays and only transmit a large portion of the rays which areneeded for printing. Glass that would only transmit from 3600 A. to 42001s not readily available without the use of complicated filter glasses.Since glass absorbs a large proportion of the radiation which istransmitted through the quartz wall of the tube, this radiation isconverted into heat in the glass cylinder. Without an inner glasscylinder or jacket, this absorption and conversion to heat takes placein the outer rotating glass cylinder. We have found that, if the outercylinder is kept small enough in diameter to make the best use of thelaws of light, then the inner surface of the outer rotating glasscylinder is insufficient surface of attack, to remove all the heat whichis generated by absorption and, thus, the outer glass cylinder withoutthe use of an inner cylinder becomes too hot for printing purposes. Byintroducing the inner stationary glass cylinder, most of the absorptionof the unwanted emission takes place there and the outer glass cylinderdoes not get excessively hot, provided that a lively stream of air ispassed over the outer surface of the inner cylinder and the innersurface of the outer cylinder. These considerations allow of the use ofmercury vapor lamps which, insofar as present experiments have shown,have an input of up to 100 watts per inch of active length. Such lampsgive, under proper conditions of pressure and temperature, between 40and 50 lumens of radiant energy per watt input, whereas the low pressuremercury vapor lamps which have been used to date will only give about 20lumens per watt. With an input of 77 watts per inch active length (for atotal burner capacity of 3542 watts), we have found that when using a41/4" outside diameter revolving glass cylinder, printing speeds areattainable which are faster than speeds obtained on modern arc lampequipped printing machines using three times the amount of electricenergy.

Drive mechanism and delivery of print subject to printer The revolvingouter glass cylinder 20 rotates on roller supports 82, which are freelysuspended on brackets 83 attached to the two end plates 84 of themachine. A series of flexible endless belts 85, which are held tightlyagainst the outer glass cylinder 20, serve to drive the said cylinderand to convey the print subject around the printing surface of the outerglass cylinder. These endless belts 85 encompass about 2/3 to 3A of theperiphery of the glass cylinder 20, thus forming an open throat facingthe operator. As explained above, a stationary light shield 23 isprovided inside the outer glass cylinder to prevent light emission fromthis throat, thereby protecting the operator from harmful light rays andpreventing premature exposure of the light-sensitive paper at the bottomof the throat. The endless belts ascenso 85 are held in position by twofront idler pulleys 86 and a rear idler pulley 81, also idler pulleys 88and 89 and a drive roller 90. Two additional idler pulleys 9| and 92overthe drive roller serve to insure maximum surface contact of the driveroller 90 by the endless belts 85. The tension in the endless belts 85may be regulated by adjustlng the position of the rear idler pulley 81by means of adjustment screw 93, which acts through lever arms 94 and95. The drive roller 90 is driven by a belt 96 from the drive shaft of avariable speed regulator 91, which is driven by the motor 61. A manuallyoperated cable drive 98, attached at one end to the speed regulator 91and at the other to a wheel 99, enables the operator to change theprinting speed at will.

A separate or auxiliary set of endless belts |00, which are driven fromdrive roller and are held in position by idling rollers |02 and |03 andtensioning roller |04 assist in conveying the print work from theoperators platform to the entrance of the printer.. These auxiliarybelts also carry the vfinished print and original from the printer to aperforated evacuated separating drum |06. A belt |01, taken from thedrive roller 90, drives roller |08 mounted on the developing portion Bof the machine and a belt from roller |08 to the drive roller |09 of thedeveloper drives the drum H0, which carries the exposed print throughthe developing chamber of said developing portion B. A gear wheel ||2mounted on the end of the developer drum drives gear ||3 in a clockwisedirection. This gear ||3, therefore, drives gear ||4 in a counterclockwise direction which, in turn, drives gear ||5 in a clockwisedirection. This last gear ||5 meshes with a gear wheel ||6 mounted onthe separating drum |06 and, hence, drives the said separating drum in acounter clockwise direction.

The tension of the auxiliary belts |00 is regulated by adjustment screw||1, which acts through lever arms ||8, I9, and |20, to pull tensioningroller |04 either forward or backward.

It is often necessary to clean the outside of the outer glass printingcylinder 20 and, since the throat opening of the said printing cylinderis too small to allow access for cleaning purposes, we have provided amechanism for lowering the front portion of the endless conveyor beltsand 4raising the front portion of the auxiliary belts |00. Thismechanism consists of a pedal |2| running across the front of themachine and mounted on arms |22, an upright member |23 carrying the rackteeth |24 which engage pinion |25. Said upright member |23, beingconnected to the shaft of idler |26, will pull that roller down when thepedal |2| is depressed. This will let the conveyor belts 85 drop. Thegear |25 and rack |24 act to prevent too quick a drop of idler |26, andthe stop arm |21 connected to spring |28 prevents the idler |26 andconveyor belts 85 from dropping by their own weight. A pin connection500 pivotally connecting an arm |29 to upright member |23, acts to pullsaid arm |29 down and forward when the pedal is depressed. thus tendingto pull the elbow member |3| down and backward, which forces the idler|02 up and forward carrying the auxiliary belts |00 with it. Thus, agood portion of the front of the outer glass cylinder 20 is exposed forcleaning or such other adjustments as may be necessary. By depressingthe pedal a little, it is also possible to relieve the pressure betweenthe contact portions of the conveyor belts 85 and auxiliary belts |00leading to the printer, thus to enable the operator to adjust theposition of the work piece just before it enters the printer.

Print separating means The automatic separating roller |06 is in theform of a cylindrical shell having a series of perforations |32 throughthe shell and extending around the periphery thereof. A shield |33 cisome flexible non-porous material, such as oil cloth, is suspendedwithin a frame |34 around the back half of the perforated cylinder. Uponevacuating the air from the inside of the perforated cylinder |06, thisshield |33 will be drawn up against the outer surface of the cylinder,thus cutting off the perforations in the back half of the cylinder. Dueto the flexible nature of this shield and the fact that it is freelysuspended from the top, it will permit the perforated roller to sliparoundfreely. The perforations on the front half of the cylinder beingopen will draw in air and, hence. suck the exposed print coming from theprinting cylinder 20 firmly against the perforated roller |06. Theoriginal tracing or other work piece that has been copied beingunaffected by the suction of the perforated roller |06 will fall intothe trough |35 provided therefor.

A series of endless belts |36 formed of endless springs engage the fronthalf of the perforated cylinder |06 in channels |31 provided therefor inthe said perforated cylinder. These endless belts, being drivenfrictionally by the perforated cylinder |06, travel around pulley |38and the idler 89 of the main conveyor belts. The section of the endlessbelts |36 between roller 89 and the perforated cylinder |06 cooperateswith the auxiliary belts |00 to aid in conveying the exposed print andoriginal away from the printer. The section of the endless belts |36between the perforated cylinder and the top pulley |38 serves as a meansto lift the exposed print off the perforated roller |06 thereby breakingthe vacuum and transport or guide it to the entrance to the developer B.While on .this section of the endless belts the exposed print is in fullview of the operator, thus enabling him to observe the degree ofexposure and make any alteration in printing speed that may appearnecessary.

The automatic separating roller |06 is exhausted by means of exhausterblower |56, the air being withdrawn through branch ducts v|51 and |58.The main exhauster duct |59 collects the air from these branch ducts anddelivers it to the blower |56, which expels it through exhaust duct |60.The common shaft 13 of the exhauster glower |56 and cooling blower 64 isdriven from the motor 61 by means of pulleys |6| and |62 and belt |63.It is also possible to exhaust the automatic separating roller bymounting independent exhauster blowers on either end of the perforatedcylinder. This alternative method will be treated below in describingmodification II with reference to Fig. 18.

Paper guide and pick-ofi The idler roller |03 is madeup of threedistinct parts, as shown in detail in Figs. 8 and 9. There is an insidestationary shaft |39 around which are provided freely rotatableself-lubricating bearings |40 and steel rings |4|, spaced at intervalsalong the shaft, which spacing coincides with the spacing of the endlessauxiliary belts |00. Between each assembly of such bearing and steelring and adjacent the outside edge of each end assembly, there is aplate member |42 fitted around the shaft |39. These plate members |42,which serve as bearing surfaces for the ends of steel rings |4| andself-lubricating bearings |40, are rigidly aixed to a channel member|43, by means of set screw |44, which extend into the outer surface ofthe shaft |39. Y The channel member |43 extends from. one end plate ofthe machine to the other, to which end plates it is appropriatelyaflixed. The bottom and inside edges of plate members 42 are shaped tofollow the curvature of the idler |26 and the outer glass cylinder 20,respectively. This shaping of the plate members |42 forms a nipple |45,which helps to guide the work piece to be printed on to the outer glasscylinder 20, in correct position for printing. A rod |46 extends througha protruding portion |41 of the plate members |42, from one end plate ofthe machine to the other. Spaced between the plate members |42 on thisrod |46 is a series of finger members 48 which are free to rotate on therod |46 and have their other ends curved to nt against the outer surfaceof glass cylinder 20. Wire springs |49, one end of which is embedded inthe finger members |48 and the other in the rod |46, are provided tohold the ngers taut against the surface of the glass cylinder. We preferto make these ngers 48 of a suitable synthetic resin. However, as analternative construction (not illustrated) for these pick-off fingers,we may have a thin flexible steel plate attached to the tips of platemembers |42 and extending the length of the rotating cylinder. This thinsteel plate is slotted on the side next to the glass cylinder, to formfiat steel fingers. The spring action of the steel plate itself holdsthese fingers taut against the surface of the cylinder. In view of thefact that these finger members |48 are free to rotate on the bar |46,except forthe tension of the wire spring |49, they will ride over anyimperfection in the surface of the glass cylinder 20 without anytrouble. Hence, the glass cylinder does not have to be ground perfectly,nor does it have to rotate perfectly.

As the work piece including the original and print emerges from the exitside of the printer, the ngers |48 will pick it off the glass cylinderand guide it to the auxiliary belts which, with the aid of the upperportion of the main conveyor belts 85 and the endless spring belts |36,will convey it to the automatic separator described above.

The developer section The developer section B of this machine consistsof a drum type ammonia gas developer for the dry development ofdiazotype light-sensitive prints. Such a developer is described indetail in our copending application, Ser. No. 215,416, filed June 23,1938. In the modification shown herein (Fig. 1) the developing chamberis formed by the housing |50 which may be lined with a suitableinsulating material |5| to aid in preventing the condensation of thegaseous developing medium. Suitable guiding means, indicatedschematically in Fig. 1 of the drawings at |52, may be provided to holdthe print in position against the surface of revolving drum ||0 while itconveys said print throughthe developing chamber. Suitable heating means(not illustrated) are also provided in the developing chamber close tothe surface of the revolving drum at intervals around its periphery, inorder to deter condensation of the developing medium on the exposedprint.

'I'he print to be developed is delivered to the developer from theautomatic separator |06, lby the belts |36. It is picked up by therevolving drum ||0 and guide roller H3. After passing the guide rollerH3, it engages the rollers |52 and travels along the periphery of thedrum ||0 under the said rollers |52. At the exit of the developingchamber, the guide roller |53 engages the developed print and deliversit to the exit chute |54. Curved plate |55 is provided, in order to pickthe print off the revolving drum in case it does not drop off afterpassing the 'guide roller.

M odz'flcation II The modification of our invention, illustrated inFigs- 13 to 20, differs from the modification fully described above inthe following principal mechanical details: Instead of having a singleblower with branch air ducts leading to the glass printer cylinders,this modication, as shown in Fig. 18, has two separate blowers |66 oneither side of the machine, the motors of which are alternated by a makeand break switch which consists of an eccentric wheel |61 and twoterminals |68 and |69, which alternately contact the wheel |61. Thecontact wheel |61 is mounted on a shaft |10 which is driven by means ofbelt i 1| and pulleys |12 vand |13 from the shaft |14 of the main drivemotor 61 through reduction gear box |65. The ducts leading from thecooling blowers |66 to the space surrounding the mercury vapor arc tube22 and the inner glass cylinder 2| are divided into two sections |86 and|81, by a partition |88. The portion of the cooling air that is carriedby section |86 is led into the space between the mercury arc tube 22 andthe inner cylinder 2| through the openings |89. The duct section |81carries the remainder of the air into the space between the inner glasscylinder 2| and the outer revolvable cylinder 20.

In this modification, as shown in Figs. 19 and 20, the pinion |95, foradjusting the movable light shield 24, is mounted outside the lamp andhousing |96 and above the plane ofthe revolvable cylinder 20. Thisoutside mounting allows for engaging the same pinion with both theadjustment rack 36 and the curved rack mounted on the upper surface ofthe adjustable shield 24. A rod |91, xed to the pinion |95 by collar |98and set screw |99, connects the pinion |95 with an identical pinion (notillustrated) mounted on the opposite end of the revolvable glasscylinder 20. Two blowers or evacuators |15 are mounted on either side ofthe perforated separating cylinder |06, each driven by a separate motor|16. In this modification, the flexible shield |33 is mounted on thefront side of the perforated cylinder |06 and the main conveyor belt 85travels around idler |64 and up past the back of the perforated cylinder|06 around the idlers |16 and |11. Hence, the original instead of theprint is sucked against the evacuated perforated cylinder i 06 and iscarried to the front of the machine through passage |84, where it isremoved from the separating cylinder |06 and placed in trough |18,provided for that purpose. The print which is not affected by thesuction of the separating cylinder |06 is carried up to the entrance oflthe developer by the main conveyor belts 85 through the channel |19,formed by guide plates |80 and |81. A series of rocker arms |82 areprovided below the separating cylinder |06, to guide the print andoriginal after leaving the auxiliary belts |00 before they reach theseparating cylinder |06. These rocker arms |82 may be pivoted clockwisearound rod |83, to allow the operator to remove the exposed print andoriginal before the former enters the developer.

A blower 200, operated by motor is mounted at the top of the developersection (Fig. 18) to facilitate the exhaustion of residual ammonia fumesfrom the space surrounding the developing chamber. A similarinstallation may also be used on modification I. A starting box 202,operated by handle 203, is provided to throw the motors in.

The drive mechanism for this modification differs from that ofmodification I in that the drive for the perforated automatic separatingcylinder |06 is taken directly from drive shaft |90 by means of thechain drive ISI, which engages sprocket wheel |92, thus driving pinion|93. Gear wheel |94, which is in engagement with pinion |93, is mountedon the shaft 204 of the perforated cylinder |06. The perforated cylinderitself is mounted on either end in housing 205, a ring bearing 2|0 beingprovided between the two surfaces. The shaft 204, which is connected tothe shell of the perforated cylinder by two sets of spokes 2|| at eitherend of the cylinder, is journaled in a thrust bearing surface 2|2 ofhousing 205. The openings 2|3, provided in the end housings 205, allowfree passage of the air out of the perforated cylinder and into theexhauster blowers |15, which expel it to the surrounding atmosphere. Theauxiliary belt system |00 of this modification is driven from theperforated cylinder by means of chain drive 206, which engages asprocket wheel 201 mounted on the shaft of the auxiliary belt driveroller 208. The mechanism for lowering the main conveyor belts to givethe operator access to the printing cylinder is provided with a counterbalance 209, in place of the rack and pinion of modification I.

In place of the revolving glass cylinder -20, described in both of theabove modifications of our invention, we may use a stationary curvedglass surface 232, as illustrated in Figs. '7 and 7a. When using such astationary curved surface, the stationary envelope surrounding themercury vapor arc lamp 22 may be either the same cylindrical glass tube2l as is used with the rotating glass cylinder, or it may be a curvedglass envelope 230 which is open on one side. When the cylindricalenvelope 2| is used as illustrated in Fig. 7, the cooling media iscirculated through the burner assembly in the same or a similar manneras is described above in connection with the revolving glass cylinder20. In this case, the removable shield 23| serves to close off the openside of the stationary curved glass surface 232 and, thus, maintains aslight pressure in the area around the burner. When the curved glassenvelope 230 is used as illustrated in Fig. 7a, the cooling media may becirculated through the burner assembly in the same manner as describedfor the revolving glass cylinder 2|)A or it may be introduced throughslots 233 in the removable shield 23Ia along one side of the burner andremoved through similar slots 234 along the opposite side of the burner.In either of these substitute printer assemblies, the work piece iscarried across the curved glass surface 232 by means of a series ofendless conveyor belts 235 which are driven by drive pulley 236 from themotor and speed regulator 231. 'I'he tension in the conveyor belts maybe regulated by adjusting either idler 238 or 233. These latter alsoserve to insure maximum contact of the conveyor belts 235 with the drivepulley 236. Idler pulleys 240 and 24|, positioned at the point of entryand exit, respectively, lead the conveyor belts around the printingsurface of the curved glass surface 232. The cooperating apparatus, suchas automatic separating means |06, light shields 23 and 24, auxiliaryconveyor belts |00 and |36, developer B, blower and blower ducts, meansfor removing the lamp assembly, etc., can be adapted to these substituteprinter assemblies with slight modifications.

We desire to have it understood that while the modifications of ourinvention, particularly described above, constitute practicalembodiments of our invention, we do not limit ourselves strictly to theexact details, herein illustrated, since manifestly they can be variedsomewhat without departing from the spirit and scope of our invention,as defined in the appended claims.

What we claim as new is:

1. In a printing machine for light-sensitive materials, ,the combinationwith a vapor discharge tube as the source of light and lighttransmitting means over which the material to be exposed is passed of alight transmitting stationary cover positioned between the said lighttransmitting means and the light source which will absorb most of theunwanted radiation converting it to heat, and means to alternate astream of cooling medium between the right and left end of the vaportube in the area between said stationary cover and the first mentionedlightl transmitting means.

2. In a printing machine for light-sensitive materials, the combinationwith a hollow rotatable light transmitting cylinder over which thelight-sensitive material is passed of a hollow stationary lighttransmitting cylinder having within it a mercury vapor discharge tube as.the source of light, said stationary light transmitting cylinder andmercury vapor discharge tube being mounted within the rotatable hollowlight transmitting cylinder, means to alternate a stream of coolingmedium between the right and left end of the vapor tube in the areabetween the stationary light transmitting cylinder and the hollowrotatable light transmitting cylinder, and means to meter smallquantities of the cooling medium into the area between the mercury vapordischarge tube and the stationary cylinder at each alternate passagethereof.

3. In a printing machine for light-sensitive materials, the combinationwith a hollow light transmitting cylinder over which the light-sensitivematerial is passed of a luminescent tube within the hollow lighttransmitting cylinder, a second hollow light transmitting cylinderwithin the first mentioned hollow cylinder and surrounding theluminescent tube, and means for causing a current of cooling air to flowthrough the ring-shaped areas between the two hollow cylinders and theinner hollow cylinder and luminescent tube.

4. In a printingV machine for light-sensitive materials, the combinationwith a rotatable hollow light transmitting cylinder having a hollowstationary light transmitting cylinder and light source mounted thereinof a means for alternately blowing cooling air first from one endandthen the other through the said cylinders and around the light sourcecomprising blower means and means for periodically reversing the iiow ofair. 1

5. In a printing machine for light-sensitive materials, the combinationwith a rotatable holloW light transmitting cylinder having a stationaryhollow light transmitting cylinder and a light source mounted therein ofa means for alternately blowing cooling air first from one end and thenthe other through said cylinders and around the light source comprisingla blower, a filter means on the intake thereto, a Y-shaped air ductleading from the blower to the ends of the light transmitting cylinder,a nip valve mounted in the crotch of the Y-shaped air duct toperiodically reverse the flow of air, and means to actuate said flipvalve. Y

6. In a printing machine for light-sensitive materials, the combinationwith a rotatable hollow light transmitting cylinder having a stationaryhollow light transmitting cylinder and a light source mounted therein ofmeans for' alternately blowing cooling air rst from one end and then theother through said cylinder and around the light source comprising twoseparate blowers positioned at either end of the hollow cylinders, andmeans for alternating the operameans within the said housing forming anenvelope around the electrode at either end of the lamp also joined insaid housing, separable electrical contact means connecting theelectrodes of the lamp with an electric circuit, slidable supportingmeans mounted on carriages connected to the aforesaid housing, andguides therefor to allow removal of the light transmitting cylinder andlamp asaunit.

8. In a printing machine for light-sensitive materials, the combinationwith a hollow cylindrically shaped light transmitting means over whichthe light-sensitive material is passed of a luminescent tube within thecylindrically shaped r light transmitting means, a second hollowcylindrically shaped light transmitting means positioned within the 'rstmentioned cylindrically shaped light transmitting means and enclosingthe luminescent tube, and means for causing a current of cooling mediumto flow through the space between the two light transmitting means.

FREDERICK W. voN MEISTER. FREDERICK W. ANDREW.

